This invention relates to a dental Pantograph wherein movement of the mandible with respect to the maxilla is measured along three orthogonally positioned transducers located at each hinge axis of the temporomandibular joint. Measurements are made by the movement of the transducers made in response to movement of the mandible with respect to the maxilla.
The human jaw includes the lower jaw bone, the mandible, which is pivotally mounted to the upper jaw bone, the maxilla, at the temporomandibular joint. The attachment is via a loose ball and socket type joint wherein a fossa on both the right and left side of the maxilla receives a condyle on both the right and left side of the mandible.
The fit of the condyles in the fossa is rather loose, allowing for extensive movement of the mandible with respect to the maxilla. Not only can the mandible move up and down with respect to the maxilla, but it can be moved backward and forward in a protrusive pathway and laterally, side to side. In executing the lateral movement, these condyles on the side on which the mandible is moving executes a rotation, whereas the condyle on the side away from the direction of movement executes orbiting. Accompanying the orbiting and rotation of the condyles are mandibulary side shifts. As such, the locus of movement of the individual condyle are complex in nature.
The complex movement of the mandible has been studied over the years in order to better understand the manner in which the teeth fit or occlude with respect to one another. Certain temporomandibular joint dysfunctions are the direct result of misocclusion of the teeth. Such misocclusion can lead to pain and stress and train of the various muscles which support and move the mandible.
Over the years, certain device have been constructed in order to measure and mimic the movement of the mandible. Pantographs have been constructed to measure the mandible movement and articulators have been constructed in order to mimic the movement of the mandible outside of the mouth in order to study and construct dental appliances for treatment of malocclusion and the like.
Because of the complex movement of the mandible as outlined above, many different expedients have been resorted to in construction of pantographic devices which could best trace and record the parameters of movement of the mandible. Many of these devices could be described; however, it is sufficient to say for the purposes of this discussion that for the most part, these devices were exceedingly tedious to use and the reproducibility of the devices, while slowly improving over the years, still leave much to be desired.
The dentist who utilizes such pantographs is a highly skilled professional whose time is exceedingly valuable. The trial and error use of the prior known pantographic devices was exceedingly wasteful for dentists' time. Furthermore, in those prior pantographic devices which produced condylar path tracings, not only was it necessary to spend an exceedingly protracted length of time in obtaining the tracings, it was then further necessary to follow the condylar path tracings while adjusting the articulator until such time that the movement of the articulator precisely followed the condylar path tracings.